1. Field of the Invention
The present invention relates to an image generating apparatus, and more particularly, it relates to an image generating apparatus comprising an ink sheet cartridge.
2. Description of the Background Art
A thermal transfer printer comprising an ink sheet cartridge is known in general, as disclosed in Japanese Patent Laying-Open No. 2003-89257, for example.
The aforementioned Japanese Patent Laying-Open No. 2003-89257 describes the structure of a thermal transfer printer comprising an ink sheet cartridge, which can be easily ejected from a cartridge mount portion by sliding an ejection member (stop member). In this thermal transfer printer, a rib portion of the ink sheet cartridge is fitted with a stop portion provided on a print head mount. The ejection member is so slid that an inclined portion thereof urges a projection of the ink sheet cartridge in an ejective direction. Thus, the rib portion of the ink sheet cartridge escapes from the stop portion of the print head mount, so that the ink sheet cartridge is ejected. The ejection member can be slid not only in nonprinting, but also in printing.
A thermal transfer printer is generally known as an exemplary image generating apparatus. FIG. 19 is an overall perspective view of an exemplary conventional thermal transfer printer. FIG. 20 is a sectional view of the exemplary conventional thermal transfer printer shown in FIG. 19. The structure of the exemplary conventional thermal transfer printer is described with reference to FIGS. 19 and 20.
As shown in FIGS. 19 and 20, the conventional thermal transfer printer comprises a chassis 101 of metal, a print head 102 (see FIG. 20) for printing, a platen roller 103 (see FIG. 20) arranged oppositely to the print head 102, a feed roller 105 carrying a paper 104, a press roller 106 pressing the feed roller 105 and a stop member 107. An ink sheet cartridge 108 storing an ink sheet 108a for transferring ink to the paper 104 is mounted on the conventional thermal transfer printer. The chassis 101 has first and second side surfaces 101a and 101b, as shown in FIG. 19. A cartridge receiving hole 101c is provided on the second side surface 101b of the chassis 101 for receiving the ink sheet cartridge 108.
As shown in FIG. 19, the stop member 107 is provided outside the second side surface 101b of the chassis 101. This stop member 107 is provided with a support shaft 107a rotatably supporting the stop member 107, an engaging pawl 107b engaging with an engaging portion 108g of the ink sheet cartridge 108, a grip 107c held by a user for lifting the stop member 107 upward (along arrow B) and a spring portion 107d supplying urging force for rotating the engaging pawl 107b of the stop member 107 downward when the user lifts up the stop member 107 through the grip. The stop member 107 has a function of inhibiting the ink sheet cartridge 108 from moving in an ejective direction (along arrow A in FIG. 19).
As shown in FIG. 20, the ink sheet cartridge 108 includes a feed bobbin 108b for feeding the ink sheet 108a and a take-up bobbin 108c for taking up the fed ink sheet 108a. A cartridge case forming the ink sheet cartridge 108 is constituted of a feed bobbin storage portion 108d rotatably storing the feed bobbin 108b, a take-up bobbin storage portion 108e rotatably storing the take-up bobbin 108c and a pair of coupling portions 108f coupling the feed bobbin storage portion 108d and the take-up bobbin storage portion 108e with each other at a prescribed distance. When the feed bobbin storage portion 108d and the take-up bobbin storage portion 108e store the feed bobbin 180b and the take-up bobbin 108c respectively, therefore, the ink sheet 108a wound on the feed bobbin 180b and the take-up bobbin 108c is outwardly exposed on the space of the prescribed distance between the feed bobbin storage portion 108d and the take-up bobbin storage portion 108e. The engaging portion 108g (see FIG. 19) engaging with the engaging pawl 107b of the stop member 107 provided on the second side surface 101b of the chassis 101 is provided on one of the pair of coupling portions 108f. The ink sheet cartridge 108 is provided with a helical compression spring (not shown), which regularly urges the ink sheet cartridge 108 mounted on the thermal transfer printer along arrow A in FIG. 19.
As shown in FIG. 20, the print head 102 has a support shaft 102a forming the rotation center of the print head 102, a head portion 102b, an arm portion 102c and a heat sink portion 102d for radiating heat from the head portion 102b. As shown in FIG. 20, further, the print head 102 is mounted on the first and second side surfaces 101a and 101b of the chassis 101 to be rotatable about the support shaft 102a. 
A printing operation of the conventional thermal transfer printer is described with reference to FIG. 20. When the print head 102 rotates along arrow C, the head portion 102b thereof comes into contact with the ink sheet 108a outwardly exposed from the ink sheet cartridge 108, as shown in FIG. 20. When the print head 102 further rotates, the ink sheet 108a comes into contact with the fed paper 104. The head portion 102b of the print head 102 and the platen roller 103 press the ink sheet 108a and the paper 104. In this state, the take-up bobbin 108c takes up the ink sheet 108a, while the feed roller 105 carries the paper 104 in a paper discharge direction (along arrow D in FIG. 20). At this time, the head portion 102b of the print head 102 generates heat, to melt the ink of the ink sheet 108a. Thus, the ink is transferred from the ink sheet 108a to the paper 104, for printing an image on the paper 104.
An operation of ejecting the ink sheet cartridge 108 from the conventional thermal transfer printer is described with reference to FIG. 19. When the ink sheet cartridge 108 is mounted on the thermal transfer printer, the engaging portion 108g of the ink sheet cartridge 108 and the engaging pawl 107b of the stop member 107 engage with each other, as shown in FIG. 19. The helical compression spring (not shown) regularly urges the ink sheet cartridge 108 along arrow A. When the user lifts the stop member 107 upward (along arrow B) through the grip 107c, the engaging portion 108g of the ink sheet cartridge 108 and the engaging pawl 107b of the stop member 107 disengage from each other. Thus, the ink sheet cartridge 108 jumps out of the thermal transfer printer along arrow A in FIG. 19, due to the urging force of the helical compression spring (not shown). Thereafter the user ejects the ink sheet cartridge 108 by manually extracting the same from the ink sheet cartridge receiving hole 101c of the chassis 101.
In the conventional thermal transfer printer shown in FIGS. 19 and 20, however, the user can eject the ink sheet cartridge 108 as described above also in printing since the stop member 107 for ejecting the ink sheet cartridge 108 is provided outside the second side surface 101b of the chassis 101. If the user accidentally ejects the ink sheet cartridge 108 during the aforementioned printing operation, therefore, the ink sheet 108a pressed by the head portion 102b of the print head 102 and the platen roller 103 may be broken, or the ink sheet 108a may be entangled in the thermal transfer printer to cause a failure in the thermal transfer printer.
In the thermal transfer printer described in the aforementioned Japanese Patent Laying-Open No. 2003-89257, the ejection member for ejecting the ink sheet cartridge is sidable not only in nonprinting but also in printing. If the user accidentally slides the ejection member in printing, therefore, the ink sheet may be broken, or may be entangled in the thermal transfer printer to cause a failure in the thermal transfer printer.
In this regard, various thermal transfer printers capable of suppressing ejection of ink sheet cartridges in printing are proposed in general, as disclosed in Japanese Patent Laying-Open Nos. 2001-38976, 11-268315 (1999) and 2-81661 (1990), for example.
The aforementioned Japanese Patent Laying-Open No. 2001-38976 proposes a thermal transfer printer, comprising an ink sheet cartridge, capable of suppressing ejection of the ink sheet cartridge in printing. In this thermal transfer printer, a projecting portion is provided on a free end of a cantilevered print head mount. The print head mount is provided with a print head, which is pressed by a platen roller in printing so that the print head mount is deflected to move the free end. Thus, the projecting portion of the print head mount engages with an end surface of the ink sheet cartridge, for suppressing ejection of the ink sheet cartridge. The ink sheet cartridge is provided with a grab, so that the user ejects the ink sheet cartridge by pulling this grab.
The aforementioned Japanese Patent Laying-Open No. 11-268315 proposes a thermal transfer printer, comprising an ink sheet cartridge, having a cartridge ejection preventing portion provided on a rotating arm rotating a print head. In this thermal transfer printer, the cartridge ejection preventing portion engages with a cartridge engaging member suppressing ejection of the ink sheet cartridge following rotation of the print head. Thus, thermal transfer printer can so inhibit the cartridge engaging member from rotation that it is difficult for the user to rotate the same, whereby the thermal transfer printer can suppress ejection of the ink sheet cartridge in printing. When the user operates the cartridge engaging member engaging with the cartridge ejection preventing portion in the thermal transfer printer proposed in Japanese Patent Laying-Open No. 11-268315, urging force is applied to the rotating arm.
The aforementioned Japanese Patent Laying-Open No. 2-81661 proposes a thermal transfer printer, provided with an ink sheet cartridge having an unexposed ink sheet, capable of suppressing ejection of the ink sheet cartridge through engagement of an engaging portion rotating following rotation of a loading arm for ejecting a take-up bobbin from a cartridge case for outwardly exposing the ink sheet with a notch provided on the ink sheet cartridge. In this thermal transfer printer, the loading arm ejects the take-up bobbin from the ink sheet cartridge in printing, thereby suppressing ejection of the ink sheet cartridge during the printing.
In the thermal transfer printer proposed in the aforementioned Japanese Patent Laying-Open No. 2001-38976, however, urging force is disadvantageously applied to the print head mount engaging with the end surface of the ink sheet cartridge when the user pulls the grab of the ink sheet cartridge in printing. Therefore, the position of the print head provided on the print head mount deviates in printing, to disadvantageously reduce printing quality.
In the thermal transfer printer proposed in the aforementioned Japanese Patent Laying-Open No. 11-268315, urging force is disadvantageously applied to the rotating arm through the cartridge ejection preventing portion when the user operates the cartridge engaging member in printing. Therefore, the position of the print head deviates in printing to reduce printing quality, similarly to the aforementioned Japanese Patent Laying-Open No. 2001-38976.
The thermal transfer printer proposed in the aforementioned Japanese Patent Laying-Open No. 2-81661, provided with the engaging portion engaging with the notch of the ink sheet cartridge and rotating following rotation of the loading arm ejecting the take-up bobbin from the cartridge, presupposes the structure having the loading arm for ejecting the take-up bobbin from the cartridge case. Therefore, it is disadvantageously difficult to apply the structure of the thermal transfer printer proposed in the aforementioned Japanese Patent Laying-Open No. 2-81661 to a thermal transfer printer employing an ink sheet cartridge having a regularly outwardly exposed ink sheet, from which no take-up bobbin may be ejected.